package firstServlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Date;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.gozap.util.BizxingConstants;

public class AuthImg extends HttpServlet  {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doPost(req, resp);
	}

	protected void doPost(HttpServletRequest req, HttpServletResponse response)
			throws ServletException, IOException {
		try{
			//设置页面不缓存
			response.reset();
			response.setContentType("image/jpeg");
			response.setHeader("Pragma", "No-cache");
			response.setHeader("Cache-Control", "no-cache");
			response.setDateHeader("Expires", 0);
			
			System.setProperty("java.awt.headless", "true");
			//在内存中创建图象 
			int width = 64, height = 27;
			BufferedImage image = new BufferedImage(width, height,
					BufferedImage.TYPE_INT_RGB);
			
			// 获取图形上下文 
			Graphics g = image.getGraphics();
			
			//生成随机类 
			Random random = new Random();
			
			//设定背景色 
			g.setColor(new Color(255,255,255));
			g.fillRect(0, 0, width, height);
			
			//设定字体 
			g.setFont(new Font("Arial", Font.BOLD, 20));
			
			//画边框 
			g.setColor(new Color(203,220,238)); 
			g.drawRect(0,0,width-1,height-1);
			
			// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到 
			g.setColor(getRandColor(190, 200));
			for (int i = 0; i < 100; i++) {
				int x = random.nextInt(width);
				int y = random.nextInt(height);
				int xl = random.nextInt(12);
				int yl = random.nextInt(12);
				g.drawLine(x, y, x + xl, y + yl);
			}
			
			// 取随机产生的认证码(4位数字) 
			String sRand = "";
			for (int i = 0; i < 4; i++) {
				String rand = String.valueOf(random.nextInt(10));
				sRand += rand;
				// 将认证码显示到图象中 
				//g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
				g.setColor(new Color(40, 94, 202));
				//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成 
				g.drawString(rand, 13 * i + 6, 21);
			}
			
			HttpSession session=req.getSession();
			
			//将认证码存入SESSION 
			session.setAttribute(BizxingConstants.AUTH_IMG, sRand);
//			System.out.println("验证码："+sRand);
			
			// 设置时间戳
			Date currentDate = new Date();
			long diffmills = currentDate.getTime();
			session.setAttribute(BizxingConstants.AUTH_TIME, diffmills);
			
			// 图象生效 
			g.dispose();
			
			// 输出图象到页面 
			ImageIO.write(image, "JPEG", response.getOutputStream());
//			com.sun.jimi.core.Jimi.putImage("image/jpeg", image, response.getOutputStream()); 
			
		}
		catch(Exception e){
			e.printStackTrace();
		}
	}
	
	/**
	 * 给定范围获得随机颜色
	 * @param fc
	 * @param bc
	 * @return
	 */
	public Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}
	
}
